1. Field of the Invention
The present invention generally relates to a resonator for attenuating acoustic pressure pulsations from an engine.
2. Description of Related Art
Resonators for attenuating acoustic pressure pulsations in automotive applications are well known. The air induction systems of internal combustion engines produce undesirable noise in the form of acoustic pressure pulsations. This induction noise depends on the engine configuration and engine speed. The induction noise is caused by a pressure wave that travels from the inlet valve towards the inlet of the air induction system. The induction noise may be reduced by reflecting a wave toward the inlet valve 180° out of phase with the noise wave. As such, Helmholtz type resonators have been used to attenuate the noise wave generated from the inlet valve-opening event. In addition and more recently, resonators have been developed that change the volume of the resonator to adjust for varying frequencies of the noise wave, as engine speed changes. Previous designs however, have not provided a wide enough frequency range to attenuate various noise frequencies produced by the engine.
In view of the above, it is apparent that there exists a need for an improved resonator having broader flexibility to attenuate various noise frequencies of the engine.